package com.hwy.utils;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * @author huangweiyu
 * @version V1.0
 * @Title: 描述
 * @Description: 通用spring获取bean工具类
 * @date 2018/6/27 9:10
 **/
@Component
@Slf4j
public class ApplicationUtil implements ApplicationContextAware {

    /**
     * 以静态变量保存Spring ApplicationContext, 可在任何代码任何地方任何时候中取出ApplicaitonContext.
     *
     */
    private static ApplicationContext applicationContext;

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量.
     */
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) {
        ApplicationUtil.applicationContext = applicationContext;
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型.
     */
    public static <T> T getBean(Class<T> clazz) {
        checkApplicationContext();
        return applicationContext.getBean(clazz);
    }

    private static void checkApplicationContext() {
        if (applicationContext == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义SpringContextHolder");
        }
    }

}
